From 9999e48639b3cecb08ffb37358bcba3b48161b29 Mon Sep 17 00:00:00 2001
From: hc <hc@nodka.com>
Date: Fri, 10 May 2024 08:50:17 +0000
Subject: [PATCH] add ax88772_rst
---
kernel/arch/mips/include/asm/mmu_context.h | 137 ++++++++++++++++++++++++++-------------------
1 files changed, 78 insertions(+), 59 deletions(-)
diff --git a/kernel/arch/mips/include/asm/mmu_context.h b/kernel/arch/mips/include/asm/mmu_context.h
index a589585..cddead9 100644
--- a/kernel/arch/mips/include/asm/mmu_context.h
+++ b/kernel/arch/mips/include/asm/mmu_context.h
@@ -17,8 +17,10 @@
#include <linux/smp.h>
#include <linux/slab.h>
+#include <asm/barrier.h>
#include <asm/cacheflush.h>
#include <asm/dsemul.h>
+#include <asm/ginvt.h>
#include <asm/hazards.h>
#include <asm/tlbflush.h>
#include <asm-generic/mm_hooks.h>
@@ -73,6 +75,19 @@
#endif /* CONFIG_MIPS_PGD_C0_CONTEXT*/
/*
+ * The ginvt instruction will invalidate wired entries when its type field
+ * targets anything other than the entire TLB. That means that if we were to
+ * allow the kernel to create wired entries with the MMID of current->active_mm
+ * then those wired entries could be invalidated when we later use ginvt to
+ * invalidate TLB entries with that MMID.
+ *
+ * In order to prevent ginvt from trashing wired entries, we reserve one MMID
+ * for use by the kernel when creating wired entries. This MMID will never be
+ * assigned to a struct mm, and we'll never target it with a ginvt instruction.
+ */
+#define MMID_KERNEL_WIRED 0
+
+/*
* All unused by hardware upper bits will be considered
* as a software asid extension.
*/
@@ -88,7 +103,23 @@
return ~asid_version_mask(cpu) + 1;
}
-#define cpu_context(cpu, mm) ((mm)->context.asid[cpu])
+static inline u64 cpu_context(unsigned int cpu, const struct mm_struct *mm)
+{
+ if (cpu_has_mmid)
+ return atomic64_read(&mm->context.mmid);
+
+ return mm->context.asid[cpu];
+}
+
+static inline void set_cpu_context(unsigned int cpu,
+ struct mm_struct *mm, u64 ctx)
+{
+ if (cpu_has_mmid)
+ atomic64_set(&mm->context.mmid, ctx);
+ else
+ mm->context.asid[cpu] = ctx;
+}
+
#define asid_cache(cpu) (cpu_data[cpu].asid_cache)
#define cpu_asid(cpu, mm) \
(cpu_context((cpu), (mm)) & cpu_asid_mask(&cpu_data[cpu]))
@@ -97,21 +128,9 @@
{
}
-
-/* Normal, classic MIPS get_new_mmu_context */
-static inline void
-get_new_mmu_context(struct mm_struct *mm, unsigned long cpu)
-{
- u64 asid = asid_cache(cpu);
-
- if (!((asid += cpu_asid_inc()) & cpu_asid_mask(&cpu_data[cpu]))) {
- if (cpu_has_vtag_icache)
- flush_icache_all();
- local_flush_tlb_all(); /* start new asid cycle */
- }
-
- cpu_context(cpu, mm) = asid_cache(cpu) = asid;
-}
+extern void get_new_mmu_context(struct mm_struct *mm);
+extern void check_mmu_context(struct mm_struct *mm);
+extern void check_switch_mmu_context(struct mm_struct *mm);
/*
* Initialize the context related info for a new mm_struct
@@ -122,8 +141,12 @@
{
int i;
- for_each_possible_cpu(i)
- cpu_context(i, mm) = 0;
+ if (cpu_has_mmid) {
+ set_cpu_context(0, mm, 0);
+ } else {
+ for_each_possible_cpu(i)
+ set_cpu_context(i, mm, 0);
+ }
mm->context.bd_emupage_allocmap = NULL;
spin_lock_init(&mm->context.bd_emupage_lock);
@@ -140,11 +163,7 @@
local_irq_save(flags);
htw_stop();
- /* Check if our ASID is of an older version and thus invalid */
- if ((cpu_context(cpu, next) ^ asid_cache(cpu)) & asid_version_mask(cpu))
- get_new_mmu_context(next, cpu);
- write_c0_entryhi(cpu_asid(cpu, next));
- TLBMISS_HANDLER_SETUP_PGD(next->pgd);
+ check_switch_mmu_context(next);
/*
* Mark current->active_mm as not "active" anymore.
@@ -166,55 +185,55 @@
dsemul_mm_cleanup(mm);
}
+#define activate_mm(prev, next) switch_mm(prev, next, current)
#define deactivate_mm(tsk, mm) do { } while (0)
-/*
- * After we have set current->mm to a new value, this activates
- * the context for the new mm so we see the new mappings.
- */
static inline void
-activate_mm(struct mm_struct *prev, struct mm_struct *next)
+drop_mmu_context(struct mm_struct *mm)
{
unsigned long flags;
- unsigned int cpu = smp_processor_id();
+ unsigned int cpu;
+ u32 old_mmid;
+ u64 ctx;
local_irq_save(flags);
- htw_stop();
- /* Unconditionally get a new ASID. */
- get_new_mmu_context(next, cpu);
+ cpu = smp_processor_id();
+ ctx = cpu_context(cpu, mm);
- write_c0_entryhi(cpu_asid(cpu, next));
- TLBMISS_HANDLER_SETUP_PGD(next->pgd);
-
- /* mark mmu ownership change */
- cpumask_clear_cpu(cpu, mm_cpumask(prev));
- cpumask_set_cpu(cpu, mm_cpumask(next));
- htw_start();
-
- local_irq_restore(flags);
-}
-
-/*
- * If mm is currently active_mm, we can't really drop it. Instead,
- * we will get a new one for it.
- */
-static inline void
-drop_mmu_context(struct mm_struct *mm, unsigned cpu)
-{
- unsigned long flags;
-
- local_irq_save(flags);
- htw_stop();
-
- if (cpumask_test_cpu(cpu, mm_cpumask(mm))) {
- get_new_mmu_context(mm, cpu);
+ if (!ctx) {
+ /* no-op */
+ } else if (cpu_has_mmid) {
+ /*
+ * Globally invalidating TLB entries associated with the MMID
+ * is pretty cheap using the GINVT instruction, so we'll do
+ * that rather than incur the overhead of allocating a new
+ * MMID. The latter would be especially difficult since MMIDs
+ * are global & other CPUs may be actively using ctx.
+ */
+ htw_stop();
+ old_mmid = read_c0_memorymapid();
+ write_c0_memorymapid(ctx & cpu_asid_mask(&cpu_data[cpu]));
+ mtc0_tlbw_hazard();
+ ginvt_mmid();
+ sync_ginv();
+ write_c0_memorymapid(old_mmid);
+ instruction_hazard();
+ htw_start();
+ } else if (cpumask_test_cpu(cpu, mm_cpumask(mm))) {
+ /*
+ * mm is currently active, so we can't really drop it.
+ * Instead we bump the ASID.
+ */
+ htw_stop();
+ get_new_mmu_context(mm);
write_c0_entryhi(cpu_asid(cpu, mm));
+ htw_start();
} else {
/* will get a new context next time */
- cpu_context(cpu, mm) = 0;
+ set_cpu_context(cpu, mm, 0);
}
- htw_start();
+
local_irq_restore(flags);
}
--
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